Known from JP 2008-230265, for example, is a head rest of the generic kind, where the side parts can pivot forward by inflating wedge-shaped inflatable bodies, in order to improve the lateral support of the head. For this purpose, the inflatable bodies are provided underneath the side parts, and each presses against a lever while inflating, one end of said lever being displaced against the rear of the side part, while the other end is being pressed against an elastically deformable body that generates a restoring force in the lever that pivots the lever back when the inflatable body is emptied and thereby compresses the inflatable body.
A head rest of the generic kind is also known from DE 10 2004 003 390 A1 in which the two side parts of a head rest are adjusted by air bags.
Other wedge-shaped inflatable bodies under the side parts of head rests are known from EP 1 817 200 B1 and DE 10 2008 030 102 A1, for example.
A disadvantage of these systems is that several inflatable bodies have to be used; at least one for each part of the head rest to be moved, thus requiring a complicated structure. In the known variations, the inflatable bodies are furthermore arranged on the sides of the head rest and are therefore accessible from the outside, such that influences from the outside can impair the operation of the adjustment.